Continuous soap process



June l1, 1946. J. K. GNTHER CONTINUOUS SOAP PROCESS Filed Dec, 4

NN Mnimo cio:

ATTORNEY Patented June 11,1946

CONTINUOUS SOAP PROCESS James K. Gunther, Hinsdale, lll., assigner to Industrial Patents Corporation, corporation of Delaware Chicago, Ill., a

Application December 4, 1943, Serial No. 512,937

'I'he present invention relates to a continuous saponication process and more particularly to a process carried out in such a manner as to effect an improvement in the quality of the soap product and a maximum recovery ofthe glycerine which is formed as a result of the saponifieation reaction.

The manufacture of soap in a continuous saponication process has been 'proposed in the `prior art. A prominent factor believed to vbe essential to the success of such a process, has been the employment of a sufficiently elevated temperature to render the soap in molten form when water and other vaporizable materialsV are removed therefrom, in order to maintain iluidity in the coils, and facilitate the substantially comis claims. (cieco-41s) i plete separation of glycerinefrom-the-molten inav terial thus formed in a vapor-,separating zone. The necessity ot maintaining elevated temperatures during the reaction has"'r esid`ed primarily in the fact, that the soap product n iust be maintained in a fi'oylvable,conditiomfaslitl is formed, so that the process may be continuous in the saponiflcation coil. The application of a suill=Y cient amount of heat to liquefy the soap and liberate glycerine, however, is ordinarily destructive of the vglycerine molecule. and results in the decomposition and consequent lo'ss of a very large portion of this valuable by-product of the saponiilcation reaction. Furthermore, the vsevere character of such conditions is found to be conducive to discoloration and general depreciation in quality of the soap product which it is desired to recoverin the process.

it has also been proposed that continuous saponincation of fatty material be effected with anhydrous caustic. The employment of anhycircus caustic has generally been considered essentia] .in a continuous process in order to ac= celerate the reaction and avoid the necessity of' separating water from the saponification prodl1 ucts. The dehydrating action of anhydrous causs tic, however, has been found to have adisastrous effect on the glycerine recovery from the saponiilcation reaction, as noted from the combined yield of distilled glycerine and that contained in the soap product.

A further suggestion of the prior art is that continuous saponication be accomplished by the use of aqueous caustic soda. However, in carryingout such a process, it is inevitably necessary tov employ such a high temperature of saponiiication in order to secure the necessary fluidity of the soap product, as well as to facilitate the separation of glycerine therefrom, that-the yield of glycerine is considerably impaired. Furthermore, the use of an aqueous caustic alkali has been restricted to highly concentrated solutions so as to avoid, in so far as possible, the large amounts oi' heat otherwise required to vaporize the Water content of the 'saponication product.

'Ihe utilization of viscosity reducing agents has i been proposed to lubricate the ilow of the reaction products through thereaction zone. 'I'he amount of such diluents, however, has been too small to improve the glycerine recovery and the character of the soap product, since excessive temperatures must still be employed which are adequate to maintain the soap product in a iiuid condition.

It is an object of the invention .to provide a continuous process for making an improved anhydrous soap product.

Another important object of the invention is to provide a continuous process of saponiilcation while effecting a substantial increase in the recovery of glycerine as a by-product.

Another object of the invention is to provide a continuous process in which saponiiication is accomplished in a considerably shorter time period and at a considerably lower temperature than possible by known processes.

Another important object of the invention is to provide for improved contact between the soap forming reactants subjected to saponifying conditions.

Another object is to provide a low temperature, continuous saponication providing the maxi mum glycerine recovery and improvement in the soap product.

Other objects and advantages, if not specifically pointed out, will be apparent to those skilled in the art from the following detailed description of what is considered to be the preferred embodiment of the invention.

The invention accordingly comprises the several steps in the relation of one or more of such steps with respect to each of the others thereof, which will be exempliiied in the process hereinafter disclosed and the scope oi the invention indicated in the claims. V

The invention broadly contemplates the continuous saponication of saponiilable material with an aqueous solution of a saponifying reagent in the presence of a sufficient amount oi an inert diluent to facilitate the saponication reaction at a temperature substantially below the melting point of the pure soap when anhydrous, while maintaining sufiicient pressure in the reaction zone to avoid vaporization of the glycerine the melting point aqueous caustic uct of the saponication reaction and the amount of diluent is preferably a maior proportion of the saponiable material. The'presence of an adequate amount of inert diluent renders the soap product iiuid at temperatures substantially below of thesoap and the use of an has been found to promote the saponication reaction even at this relatively low temperature. By maintaining a sumcient'pressure on the reaction mixture to avoidsubstantial. vaporization of the inert diluent, the fluidity thereof is preserved, although if a substantial excess of the inert diluent is employed, partial vaporizationlv thereof may occur without affecting the fluidity of the mixture. At the saponiiication temperature, partial or complete vaporization of water may or may not occur, depending on the degree of pressure applied-to the reaction mixture.

More particularly, continuous saponiiication process with a relatively diiute aqueous caustic alkali solution of a concentration of about 50 per cent caustic or less by weight and in the presence of an inert diluent in an amount equal to at least a maior proportion (over 50 per cent) oi the saponiiiable material and preferably at least about 75 per cent by weight or over based on the saponiiiable material. The aqueous alkali solution, saponifiable material and inert diluent are preferably formed into `an emulsion and subjected to saponifying conditions in a reaction zone of restricted cross section, while maintaining the fluid mixture under sufiicient pressure to substantially prevent vaporization of the inert diluent and glycerine formed in the reaction. Suilicient sensible heat may then be advantageously supplied to the sa-l ponication' products to vaporize lth'e inert diluent and glycerine, and the mixture sprayed into a low pressure zone wherein the inert solvent and glycerine volatilize by partial pressure distillation and are continuously removed, leaving a comminuted soap product which is likewise continuously removed fromthe low pressure zone. It is preferred to operate in such a manner that the saponification reaction issubstantlally complete priorto supplying the required sensible heat for vaporization of the diluent and glyceriine. The water may be substantially all vaporized by the time the products emerge from the final heating stage.

The diluent used inthe process maybe any substance which is substantially inert to the reactants and the products of saponiflcation. It is preferred to employ an inert organic diluent which boils not greatly'inexcess of about 400 F. at the pressure in the lowppressure zone and which is substantially immiscible with water and the glycerine formed in th'e reaction and substantially miscible with the soap. Solvents such as certain alcohols which are miscible with water and glycerine may -be utilized provided they possess the other requisite physical properties.

th'e invention comprises a proportion the two been saponifledby the apparatus employed in vFigure 2 comprises The lower limit flor th'e boiling point of a suitable inert diluent will be governed by the. type of the process and theV ability thereof to stand elevated-pressure at the saponification' temperature. A preferred inert diluent foruse in the process is a petroleum fraction known as "Skellysolve K which has a boiling range of from 450 F. to 500 F. Other inert dluents which may be employed include kerosene, naph'tha, gas oil, toluene, xylene and certain narrow cuts of known hydrocarbon fractions or various pure hydrocarbons which would possess the desired physical properties in relation to the particular saponiable materials and saponication products which are formed. In

`some cases, non-inflammable type diluents, such as trichlorbenzene' or tetrachlorethane, may be preferred.` The saponifying reagent may consist of any material capable of converting 'an ester into an alcohol Aand an acid salt, such as caustic sodar or caustic potash. Examples of suitable saponiiiable materials include animal and vegetable fats and oils, such as tallow andl coconut oil or any organic ester susceptible to saponiiication.

Figure 1 of the drawing illustrates diagrammatically a form of apparatus which can be employed for carrying out the process of the invention. Figure 2 is a detail of the homogenizing device shown generally in Figure 1.

Referring more particularly to Figure 1 of the drawing. v I0 indicates a tank for holding a ,solution of saponifiable fat, for example, tallow,'in an inert diluent which may be prepared at a station not shown and supplied to the tank l through a conduit II and valve I2. Another tank indicated at I3 is provided for holding a solution of a saponifying reagent, for example, a caustic soda solution prepared in `the vproper concentration, and may be charged into the tank through the conduit Il and valve I6. The solution of saponifiable fat andaqueous caustic soda in the proper concentrations are drawn through 4conduits I6 and I1. respectively, by proportioning pump I8 driven by a motor I8'. The proportioning pump may be of the reciprocating piston type and is regulated to properly y streams in the correct ratio forv saponiiicatio and to force the mixture through a homogenizing device. From the proportioning pump I8, the saponiiication reactants flow through a conduit I9 to a homogenizer 20.

wherein an emulsion is formed comprising microscopic globules of caustic soda solution dispersed in the solution of saponifiable material. 'I'he emulsion may contain small amounts of soap formed by the instantaneous saponiflcation of any free fatty acids contained in the fat, which function to stabilize the dispersion of the aqueous caustic soda phase in the inert solvent medium. A

Where low quality fats containing high percentages of free fatty acids are used, it may be necessary to heat the solution of saponifiable fat stream prior to homogenization in order to insure fluidity after the free fatty acids 'have caustic. The temperature required will be determined by the amount of soap formed prior The homogenizing device shown in detail in a valve seat I8 by a heavy spring l'I mounted on the valve stem 48. The free end of the valve stem is carried by av stumng box- 89. In operato-passing the mixture through the saponification coil.

a valve v45 urged against tion, the valve l is opened by the pressure of the mixture provided by the proportioning pump Il. In flowing through the homogenizer, the mixture is subjected to severe mechanical agitation by the shearing action of the heavily loaded valve. As a result, the pressure on the mixture may be reduced from 100 pounds per` square inch to nearly atmospheric pressure. A suitable homogenizer may be any device-capable of forming a homogeneous emlusion of the products to be saponified, for example, certain types of high speed mixing .pumps have been found satisfactory.

From the homogenizer 20, the emulsionis passed through conduit 2| to a mixer 22 where any small differences in the ratio of reactants due to the reciprocating action of the proportioning pump are equalized byagitation. The mixer 22 may be provided with agitators 23 which are driven from any suitable source of power through a pulley 2l. The homogeneous emulsion, possessing a high degree of fluidity, thereafter passes through conduit 25 and pump 26 to saponification coil 28 via conduit 21.- The saponiflcation coil may be provided with any suitablerheating means, forl example, a burner 29 or oil bath to raise the temperature of the emulsifled mixture to vthat necessary for complete saponiflca-tion. This temperature will vary inversely with the length of time the mixture remains in the coil, being about 400 F. for a 'lminute reaction period and lower for longer periods of residence in the coll. The temperature of saponiflcation is preferably substantially below the melting point of the soap when anhydrous. pressure maintained in the coil is approximately 100 pounds'per square inch. As the reaction proceeds,. the character of the mixture changes from an emulsion of fat-solvent solution and aqueous caustic soda to a highly fluid. gel-like phase of uniform consistency and substantially composed of a mixture of soap. water, inert solvent and glycerlne. The entire mixture is in a highly fluid liquid phase. The uid mixture passes from the saponifcation coil through conduit 30 and into a relatively short preheating coil 3l, wherein the temperature of the reaction mixture may be increased to approximately 480 F. in order to supply suicient sensible heat thereto to facilitate the instantaneous vaporization of the inert diluent and glycerine from the soap product in the flash chamber 35. The pressure may be maintained at about 100 pounds per square inch in this coil. The coil 3i may be heated by a burner 32 or oil bath.

The reaction mixture then passes through conduit 3S to a restricted nozzle 36, from-which it is continuously sprayed into the flash chamber 85, which may be held at a relatively low pressure, preferably less than 40 millimeters of mercury absolute, to effect a substantially cornplete separation of water, glycerine and other volatiles from the soap product, Where this is desired. It is preferred -to employ a nozzle of the atomizing type to produce a spray or fine mist of the reaction mixture in the flash chamber. The flash chamber is provided with a jacket 36 through which a suitable heating medium is circulated, via conduits 3i and 38, to furnish enough heat to compensate for heat lost from the system by radiation, conduction and convection. It is preferred that the flash chamber be maintained at a temperature high enough to prevent condensation of the volatile products at which is approximately 482 F. The

existing conditions. It isl ordinarily not necessary. however, to vsupply heat to the flash chamber for vaporization, since suillcent heat for thisv purpose is preferably supplied to the reactio mixture in the preheating coil.

As the mixture enters the iiash chamber through thespray nozzle, the volatile components, including inert diluent and glycerine, immediately ilash off by partial pressure distillation, leaving solid soap particles which settle to the bottom of the chamber in the form of a fine powder.

The temperature of the soap particles and the vapors is considerably lower than the temperature which the reaction mixture acquired in the preheater as a result of heat loss in the vaporization process. and flash chamber are preferably controlled so that the temperature of the soap and vapors after flashing is reduced to about 320 F. to'350F., or to a temperature just above the boiling point of the highest boiling volatile constituent at the existing conditions. 'I'he loss of heat occasioned by vaporization of volatiles insures the solid condition of the soap in the chamber. The low temperatureY of the soap contributes materially to the formation of aproduct of high quality. The soap particles as they settle to the bottom of chamber 35 are continuously removed by a conveyor 40.

Any suitable type conveyor may be employed for continuously removing the soap while preserving soap particles as they are advanced by the screw conveyor, has been found satisfactory. The vapors separated from the solid soap particles by the flashing operation are continuously withdrawn through conduit 39 .to a condenser Il. The condensate collects in a receiver 42 and uncondensed vapors may be passed if necessary through conduit 43 to a secondary condensing system, not shown. to complete the recovery process. A relatively high degree of vacuum is preferably maintained in the flash chamber and condensing system by a pump 44, thus facilitating the continuous withdrawal of volatiles from the flash chamber. from the glycerne and water, refined and reemployed in the process. The glycerine is purified by distillation from the Water content by means not shown. The glycerine recovered in the process is found to amount to nearly per cent of the theoretical yield.

The above description is given for the production of a tallow soap for purposes of illustration only. It is to be understood that the specific conditions indicated are purely illustrative, may be varied within relatively broad limits and, in practice, will actually be governed by the particular results desired and the character of the reactants employed.

The amount of inert diluent employed is at least sufficient to render the reaction mixture flowable below a temperature at which the soap would be molten when the volatile matter is removed therefrom. Since the removal of volatile matter causes reduction in the temperature of the soap, the temperature of saponication may, in some cases, be slightly above the melting point of the pure soap but low enough to cause the formation of solid soap when such volatile matter is removed. It is preferred, however, to carry out saponification at a temperature substantially below the melting point of the pure soap in order to improve the quality of the soap product. The presence of an adequate amount of inert diluent The conditions in the heating coils The inert diluent is separated enables the saponication reaction to be carried out below temperatures at which the reaction mixture would. in the absence of the diluent, be too viscous to handle in a continuous process. It

is to be observed that the soap content progrescharacteristics of the soap product which is produced. l

In accomplishing saponication 1n the presence of a hydrocarbon type solvent, it is ordinarily desirable to employ an amount of solvent equivalent to at least- 50 to 'l5 per cent and preferably from 100 per cent to 150 per cent by weight of the saponiable material to provide a highly v of from about'300" F. to 350 F. or even lower when a longer saponication coil is utilized.

It has been found in accordance with the invention that unexpected advantages result from vcarrying,r out saponication with an aqueous caustic solution in the presence of an inert diluent in the proportions indicated above. For example, the presence of moisture facilitates carrying the saponication reaction out at considerably lower temperatures than possible under analogous conditions employing an anhydrous type caustic. Also, a remarkable and unexpected increase in yield of glycerine from the saponiilcation reaction is obtained. The latter particularly is believed to be due to the combination of the relatively low temperatures employed and the presence of moisture during the saponication reaction.

Although aqueous caustic solutions of substantially any degree of concentration maybe employed.- it has been found that best results, particularly from the standpoint of glycerine recov- It has also been noted, however, that ery. are obtained with solutions containing causr tic alkali in concentrations of about 50 per cent or less by weight. In these ranges, it is possible to recover nearly 100 per cent of the glycerinev y yield from the reaction product. The minimum concentration of caustic inaqueous solution is ordinarily determined by considerations relevant to the removal of water from the saponiflcatlon mixture. On the other hand, at least suillcient moisture is employed to dissolve the saponifying reagent at ordinary temperatures, although more concentrated solutions are possible with the use of heat. It is usually undesirable to employ aqueous caustic solutions more dilute than about 25 per cent of castic alkali by weight.

An important factor serving to accelerate the saponiilcation reaction at the relatively low temperatures resides in emulsifying the products to be saponied by passing them through an -homogenizing device. Using aqueous caustic soda, fat

and an' meri diluent and emmslfymg the mixture.

-it has been found that the actual time period necessary to complete the saponiflcation reaction may be reduced to about one sixth of that required for saponifying a similar hydrocarbon-fat mixture with anhydrous caustic and without emulsication In this way, the productive capacity of a given plant may be greatly increased. The vsaponiflcation reaction may, if desired be accomplished without emulsifying the reactants, in which event, the homogenizer is omitted and the mixture in the proper proportions passed directly to the saponication coil. When the homogenizer is omitted, however, longer reaction periods are required. As a general rule, the use of an emulsifying device has been folmd extremely advantageous in producing high quality soaps and increasing the by-product recovery.

In order to avoid the substantial, vaporization of solvent and glycerine from the reaction mixture, thepressure thereon is preferably maintained substantially constant during flow through the reaction and heating zones and this may be accomplished by means of the pressure pump 28 and by the throttling action of the spray nozzle 34. It is preferred, moreover, that the cross sectional area of the conduit from the pump 2B to the nozzle 34 does not vary greatly, so as to provide means for unrestricted ow of the reaction mixture between these two points. It is also preferred that the conduit be of'suilicient size-so that the frictional resistance developed by the flow of the reaction mixture therethrough is neg-- ligible. It will be apparent that by these means vaporization of the diluent or solvent in sufficient amount to adversely aifect fluidity of the mixture is avoided and the presence of a sufficient amount of inert diluent to render the soap product fluid is assured. Some vaporization of the volatile materials may occur o 'r may even bel desirable prior to discharge thereof into the flash chamber. However, the pressure is always regulated to insure the presence of an adequate amount of inert diluent in liquid phase to provide for the fluidity of the .reaction mixture at temperatures below the melting point of the soap product. In practice, it has been found that an inert diluent of the hydrocarbon type in the proportions indicated above provides adequate fluidity for most fats at temperatures substantially below the melting point of the soap product. As pointed out hereinbefore, however, the specific amount ofinert solvent required to achieve this condition will depend upon the conditions employed in a particular instance.

The primary function of the preheatng coil is to supply the reaction mixture with a suillcient amount of sensible heat to provide for the substantially instantaneous and complete vaporization of vaporizable materials,including glycerine and volatile diluent from the soap product asit is sprayed into the'low pressure zone. In the preheating coil, the reaction mixture is preferably raised momentarily'to a temperature at which the water is substantially completely vaporized and at which the other vaporizable constituents will be vaporized when discharged through the spray nozzle. pose'may be about 460 F. to 470 F. for a tallow saponification product using a caustic solution of about 25 per cent to 50 per cent caustic by weight. The temperature in every case will vary depending upon each specific set of operating conditions. The temperature to which the reaction mixture is raised in the preheating coil may,

The temperature required for this purv parts of the fatdiluent solution.

in some cases, be above the melting point of the soap product but owing to the fact that this condition is only attained momentarily, the glycerine recovery and quality of the soap, are unailected. In any event, temperatures high enough at the existing pressure to vaporize glycerine are to -be avoided. As a general rule, the preheating coil is less than one sixteenth of the length of the saponiilcation coil and, therefore, the residence of the reaction mixture in the preheating coil is correspondingly abbreviated. The heat supplied to the reaction mixture in the preheating coil may be sulcient to accomplish the vaporization of water, but insuiilcient to cause substantial vaporization oi' the inert diluent or glycerine at the existing pressure. An adequate amount o! heat' to substantially vaporize the water content may be supplied without further elevation of the teme perature, whereas a very substantial elevation in temperature would be required to finnish sumcient sensible heat to provide for the vaporization of water in addition to inert diluent. glycer-Y ine and other` volatile matter in the flash chamber. In this way, it is possible to further conserve the glycerine recovery and avoid deterioration of the soap product.

In some cases, particularly where it is desired to produce a soap product having a high glycerine content or where glycerine recovery is not material. the preheating coil may be eliminated. In the latter case the reaction mixture passes directly from the' saponiiication coil and through the spray nozzle into the iiash chamber. In such cases, a more volatile diluent is preferably employed to reduce the sensible heat required for vaporlzation thereof in the flash chamber. IIhe preheating coil, however,'is preferred when it is desired to effect the substantial' elimination of glycerine and other vvolatiles from the soap product in the flash chamber and avoid the use of high temperatures in the saponiiication coil, which, as pointed out above, have an adverse eiIect on the quality of the soap product and yield of glycerine.

Example 1 As an illustration of the invention, as applied to the production of tallow soap, 100 parts of a prime grade of tallow were dissolved in 114 parts of a diluent consisting of Skellysolve K. The solution was continuously homogenized with a 51.1 per cent caustic alkali solution in the proportion of 12.91 parts of caustic solution to100 'I'he resulting homogeneous emulsion was continuously passed through a saponification coil under a pressure of 100 pounds per square inch wherein the reaction proceeded at a temperature of about 400 F. A The saponification reaction was completed in this coil. The reaction mixture was passed through a preheating coil at the same pressure Where it attained a temperature of about 480 F. and thereafter was sprayed through a restricted nozzle into the flash chamber, wherein a pressure of about 12 mm. of mercury absolute was maintained. The pressure in the saponifyirig and preheating coils was maintained at approximately 100 pounds per square inch by means of the pressure pump. The time of flow for the reaction mixture through the saponication coil was about 7 minutes whereast mately 400 F.' The solid soap in the form of a parts of fat-diluent solution.

nne white powder dropped to the bottom oi' the chamber and was continuously removed-without disturbing the vacuum therein. The vapors which percentage of glycerine accounted for amounted A to 99.8 per cent of the theoretical yield.

Example 2 l As a further illustration, 100 parts of tallow were dissolved in 115 parts of Skellysolve K" This mixture was homogenized with 12.8 parts of a; 50.6 per cent caustic soda solution to 100 The resulting emulsion was saponifled at a temperature of 390 F. and pressure of 100 pounds per square inch.l

The reaction mixture was passed through a preheating coil at a temperature of 450 F. and pressure of 100 pounds per square inch and sprayed into a flash chamber maintained at a pressure of about 10 mm. of mercury. The' temperature of the ash chamber was about 338 F. The

volatile matter flashed off and was withdrawn from the chamber. The soap precipitated to the bottom of the chamber in the form of a very fine white powder. The glycerine recovery amounted to about per cent of the theoretical yield. The powdered soap produced was of good quality and capable of being directly molded into milled bar soap without further puriiication.

The lower temperatures which were employed in the last example resulted in an improvement in the quality of the soap over the preceding example.

In the process of the present invention, an outstanding improvement in the character of the soap is obtained over that possible in following prior procedures. At the high temperatures ordinarily necessary` to effect the complete removal of glycerine from a molten or plastic soap, the product is found .to have a dark brown color as distinguished from soaps made from fats oi similar grade by the conventional procedure. In contrast, soap made directly by the present process without further purification is comparable to that made by conventional boiling processes and suitable without further treatmentv for the manufacture of fine grade soaps. A particular noteworthy feature of the process resides in the low temperatures of saponiflcation which may be employed. It is thus possible to promote the sapon ication reaction at temperatures at least 40 F. or 50 F. below the lowest temperatures possible using anhydrous caustic. Furthermore, the actual saponiication period is about 10 minutes as compared to about 1 hour when Vusing anhydrous caustic under comparable conditions in anordinary continuous saponiiication process. It is, therefore, apparent that great savings are effected in equipment as well as a substantial increase in productive capacity. v

Obviously many modifications and variations of the invention, as hereinbefore set forth, may be made without departing from the spirit and scope thereof and therefore only such limitations amount of inert organic diluent having solvent properties for the saponifiable material, the

amount of water in said aqueous solution being insufficient to precipitate the soap and said inert diluent being present in a. suillcient amount to render the reaction mixture iiowable and to enable the saponltlcation'freaction to be carried out below a temperature at which the soap would be molten when the volatile matter is removed.

`2. In a continuous process for the manufacture of soap, the steps which comprisesubjecting a mixture of asaponiiiable material, an aqueous solution of a saponifying reagent and aninert organic diluent having solvent properties for the saponiable material in an amount equal to at least 50 per cent by weight of a saponiilable material to saponifying conditions of temperature and superatmospheric pressure, the amount of water in said aqueous solution being insulcient to precipitate the soap, and separating the diluent underl a reduced pressure whereby a soap of improved quality is produced.

3. In a continuous process for the manufacture of soap, the step which comprises subjecting a mixture of a saponiable materiahan aqueous solution of a saponifying reagent no stronger than about 50 per cent by weight of the saponli'ying reagent and an inert organic diluent having solvent V properties for the saponiilable material in an amount equal to at least75 per cent by weight of the saponiable material to saponifying conditions of temperature and superatmospheric pressure, the amount of water in said aqueous solution being insufficient to precipitate the soap,

whereby a soap of improved quality is produced. V4. In a process for the saponification of saponifiable material, the steps which comprise subjectj ing a fatty material `and an aqueous solution of caustic alkali in' the presence of a volatile hydrocarbon solvent for the fatty material to saponifying temperatures whereby soap and glycerine are formed, the amount of said hydrocarbon being sumcient to render the mixture iiowable at a temperature below the melting point oi the soap when the volatile matter therein has been removed and to facilitate the saponication reaction at said last mentioned temperature and the amount of ywater in the aqueous solution being insuiiicient to precipitatethe soap, and providing suiiicient pressure during the saponiiication operation to main` tc maintain the hydrocarbon substantially inthe liquid phase,'tl1e amount of hydrocarbon being for the manufacture of soap, the

suillcient to render the reaction mixture fluid below the melting point of the soap when the volatile matter therein has been removed and the water in said aqueous solution being insufilcient to precipitate the soap in the mixture, providing suiiicient 'heat in said saponifying operation to sub- Jstantially convert said fatty material into soap soapisprecipitated. 8. In a process for the manufacture of soap,y

5. A process substcnuauy as described in claim *Y 4 in which the hydrocarbon is a petroleum fraction having a boiling range of from about 400 F. to 500 F.

6. A process substantially as described in claim 4 in which the saponifying temperatures are within the range of about 300 F. to 470 F.

7. A continuous process for the manufacture of soap, which comprises subjecting a mixture of fatty material, an aqueous solution of a saponifying alkali and a hydrocarbonrsolvent for the fatty material to a saponifying operation at elevated temperature and under pressure sumcient and glycerine and discharging the reaction products into a zone of lower pressure whereby thehydrocarhon and glycerine the steps which comprise forming an emulsion of a saponiable material. an inert organic diluent a having solvent properties for the saponiable mapure soap, the amount of water in said aqueous solutionbelng insulllcient to precipitate the soap, and subjecting said emulsion to saponifying conditions of temperature and superatmospheric pressure.

9. A continuous process for the manufacture of soap, which comprises forming an emulsion of a saponiflable material, -an inert organic diluent having solvent properties for the saponiflable material and an aqueous solution of a saponifying reagent, the amount of waterin said aqueous solution being insuiilcient to precipitate the soap and said inert diluent being present in amount equal to a large proportionof the saponiable material and in sufcient amount to enable the saponiiication reaction to be conductedbelow the melting point oi the pure soap product, subjecting'said emulsion to saponifying conditions of temperature and pressure and passing the resulting product into a lowpressure zone to vaporize volatile material by partial pressure distillation and form a-eomminuted soap product.

10.*A continuous process for producing soap,

which comprises forming an emulsion of a saponiilable material, an inert organic diluent having solvent properties for the saponliiable masure distillation and to forma comminuted soap product.

11. A continuous process for the manufacture of soap, which comprises passing an emulsion of saponiflable material, a, hydrocarbon diluent in an amount equal to at least about per cent of' the saponiable material and an aqueous solution of saponifying agent through an elongated reaction zone of restricted cross section, the amount of water in said aqueous solution being insufficient to precipitate the soap, subjecting said mixture to saponlfying conditions of temperature and superatmospherlc pressure in said zone and then separating the soap and diluent products.

12.v A continuous process for producing soap,

are ashed olf and the from the reaction which comprises passing a saponiiiable material, a major proportion oi' an organic diluent having solvent properties for the saponifiable material and an aqueous solution of a saponifying reagent at saponifying conditions of temperature and pressure through a reaction zone of restricted cross section to form a reaction mixture including soap and glycerine, the amount of inert diluent beingsumcient to renderl the reaction mixture owable at a temperature below the melting point of the pure-soap, maintaining a suillcient pressure in said zone to substantially prevent vapori- .zation of the glycerine and inert diluent and discharging the mixture in iinely divided form into a low pressure zone wherein glycerine and inert diluent are flashed oii' by .partial pressure distillation to form a comminuted soap product.

13. A continuous process for the manufacture of soap, which comprises forming an emuision nf a saponiiiable material, an aqueous solution of a saponifying reagent and an inert organic diluent having solvent properties for the saponi-- able material in sufcient amount to retain the saponification mixture in a iiuid condition below the melting point of the soap product, subjecting said emulsion to saponifying conditions of temperature and pressure to form soap and glycerine, further heating the reaction mixture to furnish suicient heat to vaporize said giycerine and diluent at subatmospheric pressure while maintaining a superatrnospheric pressure thereon to prevent vaporization of said glycerine and diluent and passing the reaction mixture into a zone of subatmospheric pressure to vaporize the glycerine and diluent by partial pressure distillation and to form a comminuted soap product.

14. A processl for the manufacture of soap, which comprises heating a mixture of a saponifiable material, an aqueoussolution of a saponiiying reagent and a relatively large, amount of an inert organic diluent having solvent properties for the saponiable material to a saponifying temperture for a suiilcient period to substantially complete the saponication of said saponiable material, thereafter heating the mixture under pressure to a higher temperature for a relatively shorter time period to vaporize a substantial amount of the water and then reducing-.the

pressure on the mixture -whereby vaporization of remaining volatile substances occurs.

15. A process for 'the manufacture of soap, which comprises heating a mixture of a saponiiiable material, at least about 75 per cent by weight based on the saponiable material of an inert organic diluent having solvent properties for the saponiable material and an aqueous solution of a saponifying reagent, in a primary heating substantial vaporization of said inert diluent and glycerine occurs to form a comminuted soap Product.

16. A process for the manufacture of soap, which comprises subjecting a mixture of a saponiable material, an inert organic diluent having solvent properties for the saponifiable material in an amount at least equal tov that of the saponifiable material and an aqueous solution of a saponifying reagent under pressure to a plurality oi stages oi' heating, maintaining a temperature in an initial stage sufliciently' high to substantially complete the saponication and to form soap and glycerine, maintaining a higher temperature in a final stage to supply sufficient heat to substantiallyvaporize the water and to furnish suiiicient sensible heatV to vaporize said inert diluent and glycerine when the pressure is re.- duced and then reducing the pressure on the mixture whereby substantial vaporization of said inert diluent and glycerine occurs to form a comminuted soap product.

17. A process for the manufacture of soap, which comprises forming an emulsion of a saponifiable'material, an inert organic diluent having solvent properties for the saponifiable material in an amount at least equal to that of the saponiable material and an aqueous solution of 'a saponiying reagent, subjecting said emulsion to a temperature below the melting point of the pure soap when anhydrous, to substantially cornplete saponification and form soap and glycerine, thereafter heating the mixture to a higher tem- Derature to furnish sumcient sensible'heat to vaporize said inert diluent and glycerine when the pressure is reduced and to substantially vaporize the water content of the mixture at the prevailing pressure, maintaining a sufiicient pressure during the operation to avoid substantial ,vaporiz'ation of the glycerine and inert diluenty and then reducing the pressure lon the mixture whereby substantial vaporization of said inert diluent and glycerine occurs to form a comstage of said zone to temperatures suiiiciently high to eiect saponication, subjecting the mixture to a higher temperature in the nal stages of said zone, correlating the temperature and time of heating in said nalstage whereby the mixzone to a saponifying temperature below the melty ing point of the pure soap product and for av sufficient period of time to substantially complete the saponication and to form soap and glycerlne, thereafter heating the mixture under Pressure in a secondary heating zone to a. higher temperature is raised to a temperature at which the water is substantially vaporized at the prevailing pressure-and at which suflicient sensible heat is sup- .izing zone of reduced pressure, and separating in said vaporizing zone water, glycerine and hydro- 4 carbon from the soap.

EAMES K. GUNTHER. 

